Turf Replacement Program Impacts on Households and Ratepayers: An Analysis for the City of Los Angeles

University of California, Los Angeles (UCLA) | September 30th, 2016

Ongoing severe drought and climate change continue to strain the Los Angeles region’s water supply and have forced the City to institute water savings goals (Garcetti,

Ongoing severe drought and climate change continue to strain the Los Angeles region’s water supply and have forced the City to institute water savings goals (Garcetti, 2014). Turf replacement programs, which aim to encourage residents to replace their lawn with less water intensive landscaping, may offer benefits as part of a larger package of conservation measures. More than half of residential water use is allocated for outdoor watering (approximately 54%) (Firestone, 2015). Outdoor water use is typically considered discretionary while indoor water use is generally considered essential, making outdoor water use a good target for conservation efforts. In order to encourage turf replacement, the city launched a turf replacement program in 2009. Commercial and residential customers can receive a rebate from the utility when they replace their lawns with less water intensive landscaping. Currently, the city is offering a rebate of $1.75 per sq. ft. up to 1,500 sq. ft. This report seeks to answer two questions regarding the turf replacement program. First, under what conditions does participation in the turf replacement program provide financial benefits to households? Second, is the turf replacement program a reasonably cost effective investment for utilities and ratepayers?

Turlock Subbasin Groundwater Sustainability Plan

West and East Turlock Subbasin Groundwater Sustainability Agencies | January 6th, 2022

The Turlock Subbasin Groundwater Sustainability Plan (GSP) was adopted January 6, 2022, and covers the Turlock Subbasin (5-22.03), which has been designated a high-priori

The Turlock Subbasin Groundwater Sustainability Plan (GSP) was adopted January 6, 2022, and covers the Turlock Subbasin (5-22.03), which has been designated a high-priority basin by the Department of Water Resources (DWR). The Turlock Subbasin covers about 348,160 acres (about 544 square miles) in the northern portion of the San Joaquin Valley Groundwater Basin. Subbasin boundaries are defined by the Tuolumne River on the north, the Merced River on the south, and the San Joaquin River on the west. The eastern boundary approximates the contact between Subbasin sediments and the crystalline basement rocks of the Sierra Nevada foothills. Two groundwater sustainability agencies (GSAs) have been formed in the Subbasin. The West Turlock Subbasin Groundwater Sustainability Agency (WTSGSA) is located in the western Subbasin and covers about 60 percent of the area. The East Turlock Subbasin Groundwater Sustainability Agency (ETSGSA) covers the remaining 40 percent of the Subbasin in the east. The two Subbasin GSAs have cooperatively developed one GSP, which covers the entire Turlock Subbasin as the Plan Area. The "Get Document" link will take you to the Department of Water Resources GSP page for Turlock Subbasin, where the 1,323-page GSP submitted by Turlock Groundwater may be downloaded. Or the file may be accessed in parts by clicking the links below. Click here for further links from Turlock Groundwater. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8

Turlock Subbasin Groundwater Sustainability Plan (Revised)

West and East Turlock Subbasin Groundwater Sustainability Agencies | July 12th, 2024

The Turlock GSAs submitted the first version of the Turlock GSP to the Department of Water Resources (DWR) in January 2022. DWR determined the GSP to be incomplete in J

The Turlock GSAs submitted the first version of the Turlock GSP to the Department of Water Resources (DWR) in January 2022. DWR determined the GSP to be incomplete in January of 2024 (DWR, 2024) and identified two deficiencies. The first of these involves provision of sufficient information (namely, analysis of potential impacts on wells) to support the selection of sustainable management criteria for chronic lowering of groundwater levels. The second involves the provision of sufficient details on the projects and management actions to mitigate overdraft in the Subbasin and to provide a feasible path to achieve sustainability. Corrective actions are incorporated into this revised July 16, 2024 GSP for resubmittal to DWR. This does not represent a GSP update, which is slated for 2027. The revised GSP was adopted by the GSAs on July 11, 2024 pursuant to 23 CCR § 355.2(e)(2)(A).

Twentieth-century shifts in forest structure in California: Denser forests, smaller trees, and increased dominance of oaks

National Academy of Sciences (NAS) | January 20th, 2015

Twenty-first Annual Report of the Mojave Basin Area Watermaster

Mojave Basin Area Watermaster | May 1st, 2015

Twenty-first century hydroclimate: A continually changing baseline, with more frequent extremes

National Academy of Sciences (NAS) | March 14th, 2022

Variability in hydroclimate impacts natural and human systems worldwide. In particular, both decadal variability and extreme precipitation events have substantial effect

Variability in hydroclimate impacts natural and human systems worldwide. In particular, both decadal variability and extreme precipitation events have substantial effects and are anticipated to be strongly influenced by climate change. From a practical perspective, these impacts will be felt relative to the continuously evolving background climate. Removing the underlying forced trend is therefore necessary to assess the relative impacts, but to date, the small size of most climate-model ensembles has made it difficult to do this. Here we use an archive of large ensembles run under a high-emissions scenario to determine how decadal “megadrought” and “megapluvial” events—and shorter-term precipitation extremes—will vary relative to that changing baseline. When the trend is retained, mean state changes dominate: In fact, soil moisture changes are so large in some regions that conditions that would be considered a megadrought or pluvial event today are projected to become average. Time-of-emergence calculations suggest that in some regions including Europe and western North America, this shift may have already taken place and could be imminent elsewhere: Emergence of drought/pluvial conditions occurs over 61% of the global land surface (excluding Antarctica) by 2080. Relative to the changing baseline, megadrought-/megapluvial risk either will not change or is slightly reduced. However, the increased frequency and intensity of both extreme wet and dry precipitation events will likely present adaptation challenges beyond anything currently experienced. In many regions, resilience against future hazards will require adapting to an ever-changing “normal,” characterized by unprecedented aridification/wetting punctuated by more severe extremes.

Twenty-First Century Levee Overtopping Projections from InSAR-derived subsidence rates in the Sacramento-San Joaquin Delta: 2006–2010

California Energy Commission (CEC) | July 31st, 2012

To provide an updated synoptic assessment of vertical land motion rates in the Sacramento-San Joaquin Delta, the research team performed synthetic aperture radar interfer

To provide an updated synoptic assessment of vertical land motion rates in the Sacramento-San Joaquin Delta, the research team performed synthetic aperture radar interferometry (InSAR) on 35 radar scenes from the Envisat platform acquired from 2006–2010. The study used contemporaneously collected continuous global positioning system data to tie the InSAR results to an absolute reference frame. In accord with the researchers’ previous study from 1995–2000 (VLM00), the new results (VLM10) demonstrate general subsidence of the Delta with respect to its margins. The average rates of ~1-2 millimeters per year (mm/yr) are slightly lower than the ~3-5mm/yr rates from 1995–2000. An unexpected finding is the uplift associated with Roberts Island, in the Delta’s southeastern sector.  The time- and space-varying differences between the two solutions (VLM00 and VLM10) highlights the need to develop a physical model for the Delta. The study used the updated ground-motion rate map and the most current twenty-first century sea-level rise predictions to project when Delta levees will subside below high-water design thresholds. The study showed that the time period between 2050–2075 is a critical time period, when levees will start to fall below design thresholds, and by 2100 most Delta levees will probably do so.

Two and a half decades of United States wildfire burn zone disaster data, 2000-2025

Nature Portfolio (Springer Nature) | December 17th, 2025

Growing wildfire frequency and urban development expanding into fire-prone areas have heightened wildfire risk for wildland-urban interface (WUI) communities. When burn z

Growing wildfire frequency and urban development expanding into fire-prone areas have heightened wildfire risk for wildland-urban interface (WUI) communities. When burn zones come near or cross into communities, the heat, flames, and smoke can harm human health—directly or via psychosocial stressors—to the point of becoming a disaster. We harmonized six wildfire datasets to create the first U.S.-wide spatial dataset of wildfire burn zone disasters. Our criteria for a wildfire burn zone disaster were wildfires that burned near a community (≥96 people per km2 or met WUI criterion) and resulted in ≥1 civilian fatality, ≥1 destroyed structure, or received federal disaster declaration. We identified 6,212 U.S. wildfire burn zone disasters between 2000–2025. The annual number of these disasters ranged between 61 in 2001 and 570 in 2011 (median = 217), with an increasing trend over the study period. California had the highest number of wildfire burn zone disasters (n = 878, 14.1%). These data may inform demographic, economic, and population health research, as well as policymaking and resource allocation.

Two-dimensional and three-dimensional digital flow models of the Salinas Valley ground-water basin, California

U.S. Geological Survey (USGS) | November 16th, 1978

The Salinas Valley is a topographic and ground-water basin in central coastal California. The ground-water basin extends from Monterey Bay south­eastward along the Salin

The Salinas Valley is a topographic and ground-water basin in central coastal California. The ground-water basin extends from Monterey Bay south­eastward along the Salinas River to San Arda, a distance of 70 miles, and has a maximum thickness of 2,000 feet. Annual recharge to the ground-water basin, which is derived mostly from the Salinas River, is about 290,000 acre­feet. Annual discharge, which is mostly from pumpage but also includes the consumptive use of ground water by riparian vegetation along the Salinas River, is about 507,000 acre-feet. About 45 percent of the pumpage, or 217,000 acre-feet of water annually, returns to the ground-water system. A group of interacting hydrologic models was developed for the Salinas Valley. These models include the small-stream model, river model, two­dimensional ground-water model, and three-dimensional ground-water model. The small-stream model simulates ground-water recharge from small streams that are tributary to the Salinas River. The river model simulates ground­water recharge from and surface-water discharge in the Salinas River. The two-dimensional and three-dimensional ground-water models simulate hydraulic head in the ground-water basin. The ground-water models were calibrated by comparing water level com­puted by the models to the corresponding measured water level for both steady-state and transient-state simulations. For the steady-state simulation, which was used to calibrate transmissivity for the two-dimensional model and hydraulic conductivity for the three-dimensional model, the median deviation of the model-generated water level from measured water level was 6 and 5 feet for the two-dimensional and three-dimensional models, respectively. For the transient-state simulation, which was used to calibrate storage coefficient for the two-dimensional model and specific storage for the three-dimensional model, the median deviation of the model-generated water level (at the end of a 3-year calibration period) from measured water level was 6 feet for both models.

Two-dimensional, steady-state model of ground-water flow, Nevada Test Site and vicinity, Nevada- California: U.S. Geological Survey Water-Resources Investigations Report 82-4085

U.S. Geological Survey (USGS) | July 1st, 1962